"Are ye so foolish?" asked Apostle Paul.

Are you so foolish, acting in self-injurious manner?
Apostle Paul was no doctrine monger, wasn't he? 

"Are ye so foolish?" asked Apostle Paul.

That was asked so long ago... because some children of God did really foolish thing... they obey not the truth of the gospel. Having heard, and embraced the truth of the gospel, they later turned away from it.

Please note that one does not need to know the truth to become God's children; but because he is a child of God, he is under obligation to know and believe the truth of his eternal salvation by God's free grace.

Many children of God have only heard of fables and embraced them as the truth of the gospel. When the truth of the gospel delivered to us be the Apostles of Christ is presented to them, they believe not! Worse still, they hate it because their mind have been poisoned by the fables masquerading as truth.

This makes the question, "are ye so foolish" ever relevant in every generation, especially the present one. How would you feel if you were queried, "O foolish ones, who has bewitched you, that you should not obey the truth...?" Fools do despise being told of their folly.

Surely the momentous issue raised and dealt with is not restricted to the foolish Galatians.

Gal 3

1 O foolish Galatians, who hath bewitched you, that ye should not obey the truth, before whose eyes Jesus Christ hath been evidently set forth, crucified among you?

2 This only would I learn of you, Received ye the Spirit by the works of the law, or by the hearing of faith?

3 Are ye so foolish? Having begun in the Spirit, are ye now made perfect by the flesh?

Apostle Paul has demonstrated in Galatians 2 that those believing their justification is by their faith IN Jesus Christ have departed from the truth of the gospel. They are foolish... as demonstrated by those few rhetorical questions posed to them in Gal 3:1-5.

Take a look at this link: 
http://things-new-and-old.blogspot.my/2012/10/the-doctrine-of-justification-as.html                

Now the serpent was more subtil...

"Now the serpent was more subtil
than any beast of the field
which the LORD God had made..."

Gen 3:1a

"Now the serpent was more subtil than any beast of the field which the LORD God had made..."

2Co 11:3

But I fear, lest by any means, as the serpent beguiled Eve through his subtilty, so your minds should be corrupted from the simplicity that is in Christ.

Can you imagine, the devil having perverted and twisted a fundamental gospel truth and turned it into a lie in such a subtle manner that few among the multitudes of God's children are aware of the horrid thing that has happened. Worse still, the great scholars among the children of God actually exert their great minds to vigorously defend the lie of the devil, but reject the plain truth of God.

You ask, “what is it?” It is what Apostle Paul deals with in Galatians 2.

It is THE truth of THE gospel. It has been substituted with a subtle lie, and that lie has been received, and defended, and is propagated as the truth of the gospel. Is there a greater tragedy than this?

The truth of the gospel: a man is justified by the faith OF Jesus Christ.

The lie of the devil: a man is justified by his faith IN Jesus Christ.

The Mother Harlot teaches:

- a man is justified by BOTH his faith and his works.

She anathematizes those who believe otherwise.

The Harlot’s daughters and their followers rebelled, and have been teaching, and defending:

- a man is justified by his faith ALONE.

The Spirit of Christ revealed to Apostle Paul:

- a man is justified by the faith OF Jesus Christ.

Galatians 2

5 To whom we gave place by subjection, no, not for an hour; that the truth of the gospel might continue with you.

15 We who are Jews by nature, and not sinners of the Gentiles,

16 Knowing that a man is not justified by the works of the law, but BY THE FAITH OF JESUS CHRIST, even we have believed in Jesus Christ, that we might be JUSTIFIED BY THE FAITH OF CHRIST, and not by the works of the law: for by the works of the law shall no flesh be justified.

17 But if, while we seek to be justified by Christ, we ourselves also are found sinners, is therefore Christ the minister of sin? God forbid.

20 I am crucified with Christ: nevertheless I live; yet not I, but Christ liveth in me: and the life which I now live in the flesh I live , BY THE FAITH OF THE SON OF GOD, who loved me, and gave himself for me.

21 I do not frustrate the grace of God: for if righteousness come by the law, then Christ is dead in vain.

Righteousness comes by the faith of Christ, i.e. Christ’s faithfulness in His work of redemption for His people.

The justification of a condemned sinner before God is by the faith of Jesus Christ; it is NOT by his faith in Christ. A man's faith in Christ is a work of righteousness; the act of believing in Christ is an act of obedience rendered to a command of God by one ALREADY justified. An unjustified man, in his native state of condemnation and death cannot possibly believe!

Rom 3:23 "Being justified FREELY by his grace through the redemption that is in Christ Jesus."
Isn't this a clear as the noon day sun! Man's faith, i.e. his act of believing, is not in the equation of his justification before God. His justification is FREELY by God's grace (i.e nothing is required of the unjustified, i.e. condemned, man), and it is SQUARELY and SOLELY and WHOLLY through the redemption that is in Jesus Christ.

"Then said they unto him, What shall we do, that we might work the works of God? Jesus answered and said unto them, This is the work of God, that ye believe on him whom he hath sent." John 6:28-29. Believing in Jesus Christ is a work commanded and required by God of His children. It is true of them, and the law requires them to believe it.

Your justification before God is by the faithfulness of Christ in His work of redemption, the faithfulness that secured the righteousness needed for the justification of His people. "I have finished the work which thou gavest me to do" John 17:4. "And behold a white horse; and he that sat upon him was called Faithful and True," Rev 19:11

You frustrate the grace of God if you believe that the righteousness necessary for your justification comes by the law, i.e. by your obedience to God's law/command to believe in Jesus Christ. Apostle Paul spells out the necessary implication of such idea, aptly, "then Christ is dead in vain."

You are saying that Christ's righteousness and blood are redundant, unnecessary!

The truth of the gospel... the faith OF Jesus Christ

"That we henceforth be no more children,
tossed to and fro, and carried about with every wind of doctrine,
by the sleight of men, and cunning craftiness,
whereby they lie in wait to deceive."

Gal 2:5
To whom we gave place by subjection, no, not for an hour; that the truth of the gospel might continue with you.

The truth of the gospel... the faith OF Jesus Christ.

Does this truth continue with you? 
Or has it been  hijacked without you even knowing it?
Is the truth of "the faith OF Jesus Christ" found in the Bible translation you are using?

Let's see what it is to Apostle Paul.

Galatians 2
5 To whom we gave place by subjection, no, not for an hour; that the truth of the gospel might continue with you.
15 We who are Jews by nature, and not sinners of the Gentiles,
16 Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified.
17 But if, while we seek to be justified by Christ, we ourselves also are found sinners, is therefore Christ the minister of sin? God forbid.
20 I am crucified with Christ: nevertheless I live; yet not I, but Christ liveth in me: and the life which I now live in the flesh I live by the faith of the Son of God, who loved me, and gave himself for me.

Apostle Paul fought like a mother bear to preserve the truth of the gospel that it may continue with the Gentile believers.

Apostle Paul declared that the gospel is this: "a man is justified by the faith OF Jesus Christ," and therefore KNOWING that truth, he believes IN Jesus Christ, by whose faith he has been justified before God. Apostle Paul DID NOT say, "knowing that a man is justified by faith IN Jesus Christ, even I have believed in Jesus Christ."

Apostle Paul repeated that glorious gospel truth, "that we might be justified by the faith OF Christ." Note carefully, Apostle Paul did not say, "that we might be justified by faith the faith IN Christ."

He said it again, "the life which I now live in the flesh I live by the faith of the Son of God, who loved me, and gave himself for me."

He did not say, "I live by the faith IN the Son of God," but "the faith OF of the Son of God.

A glorious and precious gospel truth has been hijacked by a slight twist and perversion of "the faith OF Jesus Christ" into "my faith in Jesus Christ."

Very few are even aware of this great deception and robbery, and embrace the LIE as the truth! By the sleight of men, and cunning craftiness, many have been deceived, robbed of the truth of the gospel. 

"That we henceforth be no more children, tossed to and fro, and carried about with every wind of doctrine, by the sleight of men, and cunning craftiness, whereby they lie in wait to deceive." Eph 4:14.

Ever learning, and never able to come to the knowledge of THE truth

A famine... of hearing the words of the LORD." Amos 8:11

2Tim 3:7
"Ever learning, and never able to come to the knowledge of THE truth."

2Tim 4
3 For the time will come when they will not endure sound doctrine; but after their own lusts shall they heap to themselves teachers, having itching ears;
4 And they shall turn away their ears from THE truth, and shall be turned unto fables.

There will still be abundance of pulpiteering, and much attendance to such preaching BUT such are "NEVER able to come to the knowledge of THE truth" - because NO TRUTH of God's gospel proceeds from such pulpits.

In places where the truth of the gospel of grace - sound doctrine - is preached, many will not endure or remain under such faithful preaching. They will flock to places where their itching ears are tickled, and their lust for sound bytes - fables - is attended to.

Fables are now embraced as the truth and sound doctrine. None is not exempted from such folly.

Is this true of you, "ever learning, and never able to come to the knowledge of THE truth"? Drinking from a bad fountain will poison and corrupt your mind with errors and fables.

Mighty men... men of renown - Gen 6:4

The same became mighty men which were of old, men of renown.

There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown.

Who were those giants? 

Where did they come from? 

When did they start appearing? 

What is the reference to "in those days"? 

What was the giants' relationship with the union between the sons of God and the daughters of men? 

How were those giants related to the "mighty men which were of old, men of renown"?
What were they mighty for? What were they renowned for?

These are some questions that need plain answers. More is asked below.

What are your answers to them?

Does the union between a man and a woman, of whatever religious mix, produce giant offspring, man of enormous size? Is that what the passage says?

Verse 3-5
3 And the LORD said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years.

"And the LORD said, My spirit shall not always strive with man..."
These words indicate that the LORD was completely aware of what the sons of God had done even before any evil effects of their activities have manifested themselves. The Spirit of God had been contending and restraining the evil effects of the fall in the garden of Eden - for more than 15 centuries. The union between the "sons of God" and the daughters of men had set into motion a completely new epoch of moral degeneration. The time for that divine providence of restraining men in their depravity is ending. The effects of the strange union will be left to manifest themselves. The result is stated plainly in Gen 6:5 - the universal, and total moral corruption of man, "the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually." Man's end has been determined. Destruction will come.

"... for that he ALSO is flesh": he STILL is flesh despite the union with the sons of God, the spirit beings that took upon themselves flesh. The lifespan of man, which was considerably longer, was divinely shortened and reduced to a hundred and twenty years! Union with these sons of God (the spirit beings that took upon themselves flesh) brought destruction. 

It's only through union with the only begotten Son of God - the eternal Word made flesh, Lord Jesus Christ -  that the descendants of Adam are turned into the children of God and received eternal life. 

The sons of God brought destruction BUT the Son of God brought redemption.

The sons of God were spirit beings who took upon themselves human nature, who trespassed and left their own habitation, they kept not their NATIVE ESTATE in the spirit realm, in their rebellion against God.

The Son of God was the eternal Word (also spirit Being) made flesh by God; He took on human nature according to God's purpose, in order to execute the work of redemption of His people.

4 There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown.

"There were giants in the earth in those days.... when the sons of God came unto the daughters of men."

Who were those giants?
Where did they come from?
When did they start appearing?
What is the reference to "in those days"?
What was their relationship with the union between the sons of God and the daughters of men?
How were those giants related to the "mighty men which were of old, men of renown"?
These are some questions that need plain answers. What are your answers?

Men had been procreating for more than 1500 years and there were no giant offspring, zilch! There was no abnormality recorded for us. However, in those days when the "sons of God" came into the daughters of men, there were giants. The fallen angels who took upon themselves human flesh were no ordinary humans. They were giants, perhaps their physique was like that of Saul described in 1 Sam 9:12. Were they giants in a literal sense because of their superhuman size, or giants in a figurative sense because of their unusual power and immense influence? The Scriptures describe them as "mighty men which were of old, men of renown." In other words, they were giants because of their exceptional power and immense influence upon that generation. I read this at the Blue Letter Bible, נְפִיל nᵉphîyl, nef-eel'; or נְפִל nᵉphil; from H5307; properly, a feller, i.e. a bully or tyrant:—giant; thus powerful and intimidating.

There were also giants after that - after what? AFTER those days when the "sons of God" had come in unto the daughters of men. There were no giants BEFORE those days came to pass. The union of the sons of men and the daughters of men for 1500+ years had not produced any giants. The connection is obvious, the giants AFTER those days were the offspring of the union of the "sons of God" (who themselves were giants) and the daughters of men. Giants beget giants, and they universally and wholly corrupted the whole human race in that generation. All those "giants" were destroyed in the flood. The offspring of the sons of God and the daughters of men were the giants "AFTER THAT" - and THE SAME" became mighty men which were of old, men of renown.

5. And God saw the wickedness of man was great in the earth, and that, every imagination of the thoughts of his heart was only evil continually.

This is God's own diagnosis and assessment. He speaks the truth, the exact truth. He is not given to exaggeration like men do, nor understate the fact of the situation.

In what sense were they mighty men, men of renown? The effect of the immense influence by those giants - mighty men which were of old, men of renown - is stated in these words, "the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually." Gen 6:5. Many attempts to dismiss the enormity described by these plain words and insist that the world in the 21st century is like that! No matter how one wants to EXAGGERATE the evils of the present 21st-century generation and UNDERSTATE the condition in Gen 6:5, there is just no way to equate the condition described there to another period in the history of man. Take note of the universality (affecting the whole human race), and the completeness (the evil continually) of the moral corruption described.

Many choose to believe that it is the union between godly men of the elect line and the ungodly women of the non-elect line that produced literal giants! Horrid mutation took place, they explain. In addition, such a union produced mighty men, men of renown. Perhaps they may like to explain themselves a bit.

These sons of God brought destruction upon the world BUT the Son of God brought redemption for His people.

The sons of God were spirit beings who took upon themselves human nature, who trespassed, who left their own habitation, they kept not their NATIVE ESTATE in the spirit realm, in their rebellion against God.

The Son of God was the eternal Word (also spirit Being) made flesh by God; He took on human nature according to God's purpose, in order to execute the work of redemption of His people.

Read here for Gen 6:1, and Gen 6:2.
1 http://things-new-and-old.blogspot.my/2016/02/and-it-came-to-pass-after-15-long.html
2 http://things-new-and-old.blogspot.my/2016/02/they-saw-that-daughters-of-men-were-fair.html